Right-sizing vehicles

Article
Oct 20, 2009

With the diverse range of light and medium duty truck models being produced these days, fleets no longer have to buy a one-size-fits-all vehicle for their business needs. Rather, they are right-sizing to a particular vehicle class to try and squeeze greater savings from their fleet operations. In many cases, this has meant dropping down in gross vehicle weight rating.

To gain some insight into this growing trend, Fleet Maintenance Magazine editor David A. Kolman spoke with Robert Johnson, fleet relations director for the National Truck Equipment Association (NTEA). Based in Farmington, MI, NTEA is the premier association supporting the commercial truck and transportation equipment industry.

Fleet Maintenance: It wasn't that long ago that truck manufacturers didn't offer many Class 4 and 5 models. Consequently, fleets had to overload their Class 3 trucks or step up to Class 6 models, typically resulting in extra operational and maintenance costs and reduced vehicle life. Can you elaborate on this?

Robert Johnson: Going back to the 1960s and early 1970s, Class 4 and 5 chassis were available from a number of OEMs. When these went away, some fleets upgraded to Class 6 trucks, using the logic that the extra purchase cost would be offset by lower maintenance.

Unfortunately, many of the fleets that upgraded did not factor in the higher operating costs that result from reduced fuel economy and more expensive routine maintenance costs (tires, brakes, suspension parts, etc.). Also, in some cases, there was no increase in service life since many vocational applications are low mileage and vehicles are typically replaced on the basis of body condition (rust, etc.) as opposed to mechanical condition.

The fleets that went the other direction and downsized to Class 3 trucks frequently found themselves facing issues such as broken frames, excessive suspension and brake wear and premature powertrain failures due to overloading.

A number of fleets I am familiar with first downsized and then upgraded to Class 6 trucks due to excessive maintenance problems. Those that did not upgrade were quick to jump on the "super duty" chassis when they first came out, but many of those who had previously upgraded were hesitant to downgrade again due to their previous experiences with Class 3 chassis.

FM: Regardless of vehicle class, isn't the key to vehicle performance, durability, life and lifecycle savings to properly spec the vehicle for the intended application?RJ: Yes indeed. It is critical that a truck be properly matched to the application. This means that no chassis component is overloaded and that the powertrain is adequate to provide the desired level of vehicle performance.

On the other hand, if you over spec components, you are going to incur an increased first cost and may also find that your routine maintenance and operating costs are greater than expected.

I present a number of seminars through the NTEA which specifically address this topic.

FM: When did vehicle manufacturers truly begin addressing this situation by expanding their portfolio of Class 4 and 5 products? RJ: The first of the modern era Class 4 chassis appeared around 1989 and there has been a gradual expansion of availability since that time.

Originally the only Class 4s available were 60- and 84-inch CA (distance from the back of a truck cab to the center line of the rear axle) chassis cabs. But in recent years we have seen this expand to include vans, cutaway and stripped chassis in both the Class 4 and Class 5 categories and in multiple wheelbases.

At the same time, we have seen downgraded versions of Class 6 chassis slip down into the upper limits of Class 5.

FM: Why do you think it took commercial truck manufacturers so long to realize there was a void in their product lineups?RJ: I think part of the issue was a hesitation by some OEMs to cut into their existing sales of Class 6 chassis. In addition, I think that upfitters and end users were able to work successfully enough with what was available that the need for intermediate chassis was not clearly evident to the OEMs.

Fleets saw a rapid increase in operating costs through the late 1990s and into this century and started looking for ways to reduce costs. They realized that many of their vehicles were oversized and started working with body manufactures to find ways to "right size" their vehicles.

The body companies developed new designs to fit the few Class 4 and 5 chassis available, and this created a tremendous pull-through effect that lead to the development of the more and more Class 4/5 units.

FM: Obviously, if a truck is used for purposes it was not intended for, constantly overloaded or improperly spec'd, the result would be higher maintenance costs for fleets. Correct? RJ: Absolutely. Overloaded vehicles and/or misused mounted equipment will definitely suffer from high maintenance and operating costs.

FM: Even with more truck model choices, don't fleets still face the challenge of not spec'ing a vehicle that will be too much or too little for the job? RJ: One of the biggest mistakes fleet make when designing/spec'ing new trucks is to make an arbitrary decision as to what size truck they need and then try to figure out how to make it work for a given application.

When designing a new truck, you first need to define the end application and identify the critical functional requirements. You can then design the second unit/body and have a valid basis for selecting the correct chassis for your application.

The other issue is that fleets frequently fail to define their desired vehicle performance criteria and use this information as a basis for selecting the appropriate engine, transmission and rear end gear ratios. This can result in a truck with either too much, or not enough torque and/or horsepower.

In the past, OEM truck data provided guidance on designing powertrains. As the OEMs shifted to electronic media, a lot of this information was no longer available.

This means that many young fleet managers do not understand the powertrain design process. In fact, that is one of the reasons that the NTEA has started offering training seminars on vocational vehicle design

FM: For fleets that use light and medium duty trucks, hasn't size and cargo-carrying capabilities become more critical key purchasing considerations with the expanded model offerings? RJ: The expanded availability of chassis ratings has allowed fleets to better match their trucks to their requirements in terms of payload weights and cube requirements. Other factors that need to be considered include individual axle ratings, trailer towing requirements (gcwr), vehicle drive/duty cycles and mounted equipment requirements which can drive factors such as frame and suspension requirements.

FM: Have you seen any trends in the choice of a light and medium duty truck cab configuration between cabover and conventional models? RJ: There are a number of factors that influence the choice between conventional and low cab forward chassis.

FM: Is there anything maintenance shops can be doing to help fleets choose the right vehicle for their operation?RJ: The maintenance shop is ideally situated to identify chassis maintenance/failure trends associated with overloading and application mismatches. By documenting these trends and calling them to the attention of the people who spec/order new trucks, they can help to insure that future purchases are properly spec'd.

The important thing here is to be sure that you accurately identify the root problem and not just the symptom.

FM: What can maintenance shops do to help fleets keep their vehicles running efficiently - whether or not they are using the right vehicle for their operation?RJ: First, you need to accurately determine the optimum PM interval for each group of trucks. Too many fleets make the mistake of trying to make one set of criteria work for every truck in the fleet.

Optimum PM intervals can be influenced by the individual vehicle make/model, application and vehicle age.

I emphasize the concept of optimizing PM schedules. Every time you touch a vehicle you will incur a minimum of one hour of labor changes.

You need to look at all of the factors that require you to touch a truck (chassis PM, equipment PM, emissions inspections, DOT inspections, license renewal sticker placement, etc.) and establish a schedule that lets you do as many things as possible during one touch, even if it means cutting some schedules short.

Another thing to consider is to establish a good predictive maintenance program. If the mean time between failures (MTBF) for a given component is say 72,000 miles, that component should be flagged for replacement during the latest possible scheduled PM prior to the component reaching its MTBF point.

FM: Over the past several years, OEMS have been introducing environmentally friendly alternative-fueled and hybrid vehicles. At present, these types of vehicles seem best suited for certain applications, such as work trucks that use PTO-equipment and accessories and trucks used in stop-and-go applications, such as refuse. Do you see applications for this expanding?RJ: At this point in time there is no one "green" technology that works for all drive/duty cycles. As the various green technologies improve and the infrastructure for alternative fuels develops, I thing you will definitely see increased use of these technologies.

Right now very few of the green technologies have a true payback, so most applications are linked to environmental mandate, the desire to appear green or the availability of buy-down funds. Again, as the technologies become mature, the costs will come down and the paybacks will be better.

The other thing I am seeing is the greening of "conventional" trucks. The use of idle control/reduction technologies, improved vehicle and component designs, better spec'ing and improved vehicle productivity can generate fuel savings equal to the most efficient hybrids currently available at a significantly lower cost.

FM: Might these types of vehicles make sense for a maintenance shop's vehicle fleet? RJ: It depends entirely on the drive/duty cycles of the vehicles in question. If the shop truck has a low mileage duty cycle you will never see a payback for a hybrid no matter how efficient the truck is due to the first cost premium.

If it is used as a pusher truck or for plowing snow, you will probably find that the hybrid you are considering is not rated for this type of duty cycle. On the other hand, if your shop truck generates a lot of mileage and is utilized in an area where there is adequate infrastructure the use of an alternative fuel may make a lot of sense.

FM: Any finals thoughts?RJ: Fleets are under a tremendous pressure to reduce both operating and acquisition costs. Many fleets are taking a close look at current vehicle utilization practices and policies to identify ways to downsize portions of their fleets without overloading them.

This may mean designing trucks for restricted applications, which in turn means it is critical that the proper truck be assigned to a specific job.

My concern is that down the road utilization pressures may lead to another cycle of truck overloading as people lose sight of the importance of matching the trucks to the job.